Thermoelectric materials lower the temperature when an electric current is passed therethrough and have traditionally been made from a variety of semiconducting materials whose usefulness is quantified in terms of the material's "figure of merit" is defined by the relation ##EQU1## where S=the material's Seebeck coefficient in micro volts/Kelvin (.mu.V/K);
.sigma.=the material's electrical conductivity in Siemen/centimeter (S/cm); and PA1 .kappa.=the material's heat conductivity in milliwatts/Kelvin-centimeter (mW/K-cm). PA1 have a high melting point to withstand exposure to temperatures expected during actual use; PA1 be chemically stable so as not to break down over time; PA1 have low vapor pressure such that components of the material are not lost over time or during heating; PA1 have a good degree of mechanical strength, i.e., must not be brittle; and PA1 be of low density to minimize weight.
Thus, in terms of a material's thermoelectric properties, the material with the larger figure of merit is most desirable. However, to be useful as thermoelectric material, many applications require that the material also:
A variety of conducting polymers have been suggested as thermoelectric materials owing to their low density and low heat conductivity. With respect to heat conductivity, the heat transfer mechanism is via coupled lattice vibrations which do not transfer heat as efficiently as electron transfer in, for example, metals. Thus, heat conductivity of a conducting polymer is less than that of metals thereby having a positive effect on the material's figure of merit. However, to date, proposed conducting polymer thermoelectric materials have had either low Seebeck coefficients (e.g., in the range of 10-20 .mu.V/K), low electrical conductivity (e.g., in the range of 10 S/cm), or been lacking in one or more of the afore-mentioned desired material properties. For example, polythiophene-polyethylenevinylacetate doped with ferric chloride has a Seebeck coefficient of 24 .mu.V/K and an electrical conductivity 10-100 S/cm. Another proposed thermoelectric material, e.g., ferric chloride doped polyparaphenylene, has been reported to have a Seebeck coefficient of 1200 .mu.V/K at room temperature. However, this material's electrical conductivity is only 2.times.10.sup.-8 S/cm.